Telephone-exchange system.



M. L. JOHNSON. TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED AUG. 10, 1912.

Patented Feb. 25;, 1913.

IHI'

WITNEss 5 INVENTOR.

I Q I l'aimgol L JOHNLTBQYN A'r'r on 1 eluded across to .iL. A) .42

IS, ASSIGNGR TO CORWIN TELEPHGNE KHAN- ILLII'JL IS, A CORPORATION 02 ILLINGIS JELEPEO'DlE-EXGHANGE SYSTEM.

Application filed August To all whom it may concern Be it known that l, Monron L. Jo nson, citizen of the United Stat-es, residing at Chicage, in the county of Cook and State Illinois, have invented a certain new and useful Improvement in Telephone-Eschange Systems, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings forming a part of this specification.

lily invention relates to telephone exchange systems and has for one of objects the provision of improved means whereby called parties may tall: with )i-fepayment calling parties before the calling parties have deposited their tokens or otherwise operated apparatus which requires prepayment or charge before connection established.

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invention has for another its obyects the provision oi means whereby the called party may receive some manifestation to satisfy him that he is being sought by some calling party without at the same time permitting the calling party to converse with him. V

I will explain my invention in its preferred embodiment, to which embodiment the invention is not to be limited, the drawing illustrating a calling prepayment station and a called station whose lines extend to the same exchange and which lines are adapted for telephonic connection through the agency of cord connector equipment. The system, as illustrated, thus a manual telephone exchange system, though it will be apparent that the invention does not depend upon the employment of manually operated link connectors and I do not therefor limit myself to manual exchange practice.

The prepayment or precharge station A, of which there are of course number, and the called station B, which may or may not be a prepayment or precharge station, are illustrated as being each pr vided with the usual telephone equipment. including a tele phone receiver switch hook 1 having a non mal contact for connecting the line sides through a signal hell 2 an a condenser 3 l when the telephone e is upon its witch hook. siv'tch hook has an alternate cont ct u a. iy the telephone receiver e and te l n hitter are in- Specilication of Letters Patent.

l i i i i I l i i relay 12 when the calling llatented 25, iltlhi.

6, 1912. Serial No. 714,423.

phone receiver is removed from its switch hook. Assuming that the invention is embodied in the manual exchange s stem illustrated nd thatthe party at station A is initiating a call, the receiver a atthe calling station A. is free of its switch hoolr to permit said switch hook inet allically to corn nect the sides of the calling line whereby circuit is established through the line relay which in turn establishes circuit through the line signal 7. In case of a manual exchange system, an operator having charge of the signal 7 will insert an answering plug 8, of the selected one of number of link connectors with which the operator is provided, within the jacl; of the calling line thereby to operate the cutoll relay 9 there by to eitace the calling line signal at 7, all as is well understood by those skilled in the rt. The cutoit' relay circuit includes a re- 10 that closes one gap the circuit of he calling subscribers supervisory signal 1. The remaining gap in this supervisory :ig'naling circuit is opened by the supervisory suhscribers telephone receiver is tree of its hook, circuit for this relay being traceable from the upper grounded winding of the dillerential relay 13, the upper coil of supervisory relay 12, the tip of the answering plug 8, the tip jack spring of the calling line, the telephone bridge at the calling station A, the sleeve jack spring of the calling line, the sleeve contact of the answering plug 8, the lower winding of supervisory relay 1%, the lower winning or" diilerential relay 13 to the grounded battery 14 which may be a bahv tery common to the exchange. When the .calling subscriber restores his receiver upon its switch hook the circuit just traced is broken at the switch hook whereby the display hy-the calling suhscriber s supervisory signal 11 is effected. The relay 13 is introduced in practising my present invention. The two coils of this relay are ditierentially wound so that the. relay is not efi'ectively energized when both of these coils are included in circuit by way the telephone .5 idge at the cailirc station is, this tel phone bridge serving to make these coils c' .qual oopo ing effectiveness. The operator manip "a,

her listening lacy 15 to bridge her telephone set 16 between the sides of the connecting link circuit for the purpose of receiving "from the calling station the number of the desired line. The operator will thereupon lake the connecting plug 9 for use and in sort the same within the spring jack 1? of the line leading to the called station sumed to be station E, operator first having made the test with the tin of the plug 9 if the system is a multiple switch board system and as testing facilities are well known such will not be described in connection with my present. invention. The connecting plug 9 having been inserted, ringing current is sent to the signal bell at the called station upon the depression of a ring ing key 18 as is well understood by those skilled in the art. When. the called subscriber responds his line sides are metalligap in this supervisory signaling circuit,

having been closed by the operation of a relay 21 whose circuit was established when the plug 9 was inserted within the called line jack 17, the circuit for this relay 21 being traceable from the battery 14, the heel of the plug 9, the thirnble of the jack 1?, to the grounded cutoff relay 22.

As is well known, when the called subscriber restores his receiver upon its switch hook the circuit for the relay 19 is opened so that the circuit for the supervisory signal 20 is established. The called subscriber now having his telephone tree of its switch hook and his supervisory relay19 being new energized, a circuit is established which is traceable from the right hand grounded armature switch of relay 21 and its now on gaged contact, the upper armature switch of relay 19 and its now engaged contact, the lower and now unattracted armatureswitch of relay 22 and its contact, the relay :23, to the grounded battery 14:. The two upper armature switches of relay 23 are provided with normal contacts that are connected through a condenser 2d and the two lower armature switches of this relay 23 are provided with normal contacts that are connected through a condenser 25. When the relay 23 is denergized the tips or the plugs 8 and 9 (assuming the ringing key 18 to be in its idle position) are connected by way 01- the serially related upper armature switches of relay 23, their normal contacts, and the condenser 24, while at. the same time the sleeves of the plugs S and 9 are connected by way of the serially related lowerarmature switches of relay 25, their normal contacts, and the condenser \Vhen the relay 23 is energized, as was previously described, its armature switches are disengaged from their normal contacts so. that a gap is introduced in the connec possess lions uniting the tips of the plugs 8 and 9 and a gap is introduced in the connections uniting the sleeves of the plugs 8 and 9 so as to prevent the link connector employing the plugs 8 and 9 from normally pertorm- .ing its function of telephonically uniting calling and called stations, voice currents impressed upon the calling line by the call ing subscriber being unable to jump the gaps in the sides of the link connector that are formed upon the energization of the relay 23, it being incumbent upon the call ing party to deposit the coin or otherwise perform some act that will impose the cost of the connection upon him before the gaps that telephonically separate him from the called party are closed. The calling party awaits instruction from the exchange before performing the act that will place him in full telephonic connection with the called party, and such instructions are desirably :uitoinatically conveyed by means of a phonograph 26 which. speaks into a telephone transmitter 27 at intervals, the circuit of this transmitter including a primary coil 28 from which current is induced into a secondary coil 29 included in. local circuit with a telephone receiver 30 placed before a telephone transmitter 31. The terminals oi the transmitter 31 are connected with the alternate contacts of the can interinediate armature switches of relay 23 which constitute terminals of the answering end. of the link connector joining the called and. calling lines and when the armature switches of relay 23 are attracted the speech from the phonograph 26 is transmitted to the calling subscribers telephone receiver 4. The phonograph may be arranged to give the calling subscriber some suitable notice such as Drop a nickel please or Register your connection The top and bottom armature switches of relay 23 constitute terminals of the connecting end or the link connector and are pro vided with alternate contacts that constitute terminals of a coil 32 secondary to the primary 28. When the armature switches of rela are attracted the coil 82 is in circuit with the called station. The phonograph 26 may be caused to say into the I transmitter 27 lVhat is your number please and the called party will respond so that the calling party may know whether or not he has secured the right station, the coil 32 becoming a primary when the called party responds to the request for his number, whereby the telephonic current in the coil. 32 sets up similar current in the coil 29 and receiver 30, the receiver 30 causing the operation of the transmitter 31 and thereby the operation of the telephone receiver l at the calling station. The phonograph ztl does not instruct the calling subscriber to deposit his coin until the coil 32 is "connected with the call ing line, and the calling line cannot be connected with the coil 32 until the called sub-- scriber-has responded,'by which arrangement the message Drop a nickel please conveyed to the calling subscriber also inmet 2'2 is energized its lower armature switchforms the calling subscriber-that the called.

subscriber has responded.

The calling stationJl. is shown as being equipped with a switch33 whose contacts are engaged by a token as. when deposited (though the invention is notto be limited to the employment of token receiving appara tus at- ,the calling station), a path being established upon the engagement of the contacts 33 which may be traced from the grounded one of these contacts through the other Contact, the switch hook 1 at the calling station and. its alternate contact the sleeve spring of the jack of the calling line, the sleeve contact of the answering plug 8, the lower winding of the supervisory relay 12, the lower winding of the difierential re lay 13, to the grounded battery 14. Each winding of each relay 12,13 may be wound to 100 ohms'rsistance, assuming a voltage of fortyvolts for the battery 14. Thus when the contacts 33 are engaged the difierential coils ot relay 13 are thrown out of balance to cause its armature to be operatet whereby circuit is established through the relay 22.

As the contacts 33 are closed by the token in passing 1 provide a locking circuit for the relay 22 which may be traced from the grounded battery 14, the winding of the relay'22, the upper armature switch of this relay to the righthand grounded armature switch of relay :21; this locking circuit being broken when circuit for the magnet.21 is interrupted upon the withdrawal of the connecting plug 9 from the jack 17' of the called line. /Vhen the msgis attracted to intercept the circuit which was previously established through the magnet 23 as a consequence of the energization of the called subscriber supervisory relay 1% whereby the upper armature switches of relay 23 and their normal contacts are serially included in the tip connection between the answering and connecting plugs 8 and 9 and the lower armature switches of relay 23 and their normal contacts are'serially included in the sleeve connection between the answering and connecting plugs. The connection bet-ween the calling and called stations is now fully established and each station may communicate with the other." When the parties are through supervisory signals are conveyed to the operator inthe usual way whereupon the operator withdraws the answering and connecting plugs to restore the equipment to its idle condition. y 7

Nhile l -have herein shown particularly. described the preferred eibotliinent ot spirit of the-invention, but

my invention 1 do not wish to be limited to the precise. details or construction and circuit arrangement illustrated as changes readily be made withoutdeparting'from the l hus having described my invention I claim as new and desire to secure by Letters- Patentthe following:-

1. A telephone exchange system including telephone lines extending from subscribers stations to an exchange at some of which stations are located devices requiring opera tion by calling s'ubscribers'at't-er responses by called subscribers in order to complete connection between calling and called subscribers there being means at the-subscrib- "ers stations cohperating with these devices and operable by responding called subscribers; l nt: connectors at the exchange for uniting lines in conversation; switching mechanism for breaking telephonic connec;

'tion between callingand called stations for telephonic current impressed upon calling lines at calling stations; and electro-magnetic mechanism governed by the aforesaid d'evices calling stations equipped therewith in cooperation with the aforesaid means at stations oi responding called subscribers for operating said switching mechanism to comv plete connection between calling and called stations. l I

2. A telephone exchange system'including telephone lines extending from subscribers stations to an exchange at some ofwhich stations are located devices requiring operation by calling subscribers after responses by called subscribers; linkconnectorsatthe ex-. chan e for uniting lines in conversation;

switching mechanism in the link connectors for permitting and preventing passage of electromagnetic mechanism included int-he link connectors within the control of called subscribers and operated by called subscrib ers equipment when called subscribers respend to break telephonic connection bescribers there being means at the sub- 7 I I scribers stations cooperating wit" these devices and operable by responding. called subscribers5linl: connectors at the exchange 105 telephonic current from calling stationsg for uniting lines in conversation; switching .mcclnmism included in the link connectors for breaking" telephonic connection between celli; sud nlled stations for telephonic nipressed upon calling lines at call stations; and electromagnetic mechc :oism governed by the aforesaid devices at selling stutions equipped therewith in cooperation. with the aforesaid means at sta tions of responding called subscribers for operating said switching mechanism to complete connection between calling and called stations.

A. telephone exchange system including lllfijlrl'lUllfl lines extending from subscribers stations? to on exchange at some of which tions are located devices requiring operation by coiling subscribers eiiter responses by. called subscribers in order to complete otion between calling and called subscr. re being means the subscribers s minus cooperating with these derices end opernble responding called so ib U1 link connectors at the exchange jt'oru lines in conversation; switchinpymechr iism included in the link cons for breaking telephonic connection calling and culled stations for telephonic current impressed upon calling lines at culling stations; electromagnetic mechais'm governed by the aforesaid devices ill) "ling ststions equipped. therewith in co ration with the slot said. means at stous of reopt, ding; called subscribers for 1 operating suicl switching mechanism to compiste commotion li)etweeli collingund celled ions; mid t-dectromugnchic moons in the link coir tors :lor completing telephonic t, meets culling silt celled stoepbonic current impressed upon ltllQCZlllQCl stations when televction is broken between cellststions for current impressed lines utcallingst tions, there ct responding cs d stations al t me svsten includi sube of ,l requir i-uuscribers otter Ibcrr in or er to between calling and heir means the 1th these called at toe exchange itiou; switchlephonic concclled staimpressed stations;

at will tmechnmsm Lessons stations for current impressed upon calling lines at calling stations.

6. A tele hone exchan 'e *stem lllClllClll'l b b telephone lines extending from subscribers stations to an exchange at some of which stations are located dcvicesrequiring operation by calling subscribers after responses by called subscribers; link connectors at the exchange for uniting lines in conversation; switching mechanism; electro-mug'netic mechanism vwithin the control of called subscribers and operated by called subscribers equipment when called subscriber-s respond to break telephonic connection between calling and called stations for telephonic current impressed upon culling lines at calling stations; elect-ro-maguetic mechanism operated by the aforesaid devices at calling stations equipped therewith for operating said switching mechanism to complete connection bet-ween calling and called stations; and means for completing telephonic connection between calling and called stations for telephonic current impressed upon celled lines at called stations when telephonic connection is broken between calling and called stations for currentimpressed upon calling lines at calling stations.

1. A telephone exchange system including telephone lines extending from subscribers stations to an eltcbsngc at some of which stations are located devices requir ing operation by calling subscribers after responses by celled subscribers in order to complete connection between calling and called subscribers, there being menus at the subscribers" stations cooperating with these devices and operable by responding celled subscribers; link connectors at the exchange for-uniting lines conversation; switching mechanism included in. the link connectors for breaking telephonic connection between coiling and called stations for telephonic current impressed upon calling lines at calling stations; electromagnetic mechanism "(Werned b 1 the aforesaid devices at culling ED 4 stat-ions equipped. therewith in cooperation with the aforesaid means at stations of responding culled subscribers for operating said switching mechanism to complete connection between calling and called stations; and means for completing telephonic connection between calling and called stations for telephonic current impressed upon culled lines at culled stations when telephonic connection is broken between calling and mechanism called stations for current impressed upon calling lines at calling stations.

8. A telephone exchange system including telephone lines extending from subscribers stations to an exchange at some or which stations are located devices requiring operation by calling subscribers ai'ter responses by called subscribers; link connectors at the excl ange for uniting lines in conversation; switching mechanism included in the link connectors; electromagnetic mechanism within the control or called subscribers and operated by called subscribers equipment when called subscribers respond to break telephonic connection between calling and stations for current impressed upon callinglines at calling stations. N

9. A telephone exchange sytem including telephone lines extending from subscribers stations to an exchange at some of which stations are located devices requiring: operation by calling subscribers after responses by alled subscribers; link connectors at the exchange for uniting lines in conversation;: electro -1nagnet1c within the control of called swit hing in echanism subscribers and operated by called subscribers equipment when called subscribers 'espond to break telephonic connection be- I tween calling and called stations tor telc; phonic current impressed upon calling lines at calling stations; electtn-niagnetic mecha- 1 111cm operated by the aforesaid dev ces at' calling stations equipped therewith for operating said switching mechanism to complete connection between calling and called stations; and means brought into association with calling lines by said switchin mechanism w'hen operated upon response or called subscribers for sending current to calling subscribers equipment to notify calling subscribers to operate their aforesaid devices and by such notification to indicate to calling" subscribers that called subscribers have responded.

10. A telephone exchange system including telephone lines extendingfrom sub scribers stations to an exchange at some of which stations are located devices requiringoperation by calling subscribers after responses by called subscribers; link connectors at the exchange tor uniting lines in conversation; switching mechanism included in the link connectors; electromagneticmechanism within the control of called subscribers and operated by called subscribers equipment when called subscribers respond to break telephonic connect-ion between calling and called stations for telephonic current impressed upon calling. lines at calling stations; electromagnetic mechanism operated by the atoresaid devices at calling stations equipped therewith for operating said switching mechanism to complete connection between calling and called stations; and

meansbrought into association with calling lines by said switching mechanism when operated upon response of called subscribers for sending, current to calling'subscribers equipment to notify calling subscribers to 'operate their aforesaid devices and by such notification to indicate to calling subscribers that called subscribers have responded.

1. telephone exchange system includtelephone lines extending from subscribs stations to an exchange at some oil which ati are located devices requiring operation by calling subscribers after responses by called subscribers; link connectors at the exchange for uniting lines in conversation; switching mechanism; electro magnetic mcchanisrn within the control of called subscribers and operated by called subscribers equipment when called s bscribers respond to break telephonic connection between call ing'and called stations for telephonic current impressed upon calling lines at calling stations; electromagnetic mechanism operated by the aforesaid devices at calling stations equipped therewith for operating said switching mechanism to conplete connection 'z-between calling and called stations; means /lor completing telephonic connection be- 05 tween calling and called stations for telephonic current impressed upon called lines at called stations when telephonic connec'-. tion is broken between. calling'a'nd called stations for current impressed upon calling lines at calling stations; and means brought into association with calling lines by said switching mechanism when operated upon response of called subscribers for sending current to calling subscribers equipment to 1 notify calling subscribers to operate their ,toresaid devices and by such notification to indicate to calling subscribers-that called subscribers have responded.

12. A telephone exchange system includ- 2 i ing telephone lines extending from subscribers stations to an exchange at some of which stations are located devices requiring operation ;by calling subscribers after" responses by called subscribers; link connectors at the exchange for uniting lines in' conversation; switching mechanism included in the link connectors; electro -magnetic mechanism within the control of called subscribers and operated by called subscriberfi equipment ill when called subscribers respond to break telephonic connection bet-ween calling and called stations'for' telephonic current in pressed upon calling lines at calling stations; electromagnetic mechanism operated by the aforesaid devices at calling stations.

ing mechanism when operated upon response oi called subscribers for sending cur-- rent to calling subscribers equipment to notify calling subscribers, to operate their aforesaid devices and by such notification to indicate to calling subscribers .that called subscribers have responded.

13. A telephoneexchange system including telephone lines extending from subscrib ers stations to an exchange at some of which stations are locateddevices requiring operation by calling subscribers after r ponses by called subscribers; link connectors at the .ex change for uniting lines in conversation; switching mechanism electro magnetic mechanism within the control of called subscribers and operated by called subscribers equipment when called subscribers respondto break telephonic connect-ion between calling and called stations for telephonic current impressed upon calling lines at calling stations; electromagnetic mechanism operated by the atoresaid'devices at calling stations equipped therewith for operating said switching mechanism to complete connection between calling and called stations; means brought into association with calling lines by said switchin g mechanism when operated upon response of called subscribers for sending current to calling subscribers equipment to notify calling subscribers to operate their aforesaid devices and by such notification. to indicate to calling subscribers that called subscribers have responded; and means governed by'said switching-mechanism for completing telephonic connection between called stations and the exchange prior to the complete establishment of telephonic connection between calling and called stations whereby called stations may be in structed to mention their numbers. 7

14. A telephone exchange system including telephone lines extending from sub scribers stations to an exchange at some of which stations are located devices requiring operation by calling subscribers after responses by called subscribers; link conn'ectors at the exchange for uniting lines in ineaees conversation; switching mechanism included in the link connectors; electro-mag netic mechanism within the control "of called subscribers and operated by called subscribers equipment when called -subscribers respond to break telephonic connection between calling and called stations for telephonic current impressed upon calling lines calling stations; electro-magnetic mechanism operated by the aforesaid devices at calling stat-ions equipped therewith for operating said switching mechanism to comp ete connection between calling and called stations; means brought intodassocia tion with :alling lines by said switching mechanism when operated upon response of called subscribers for sending current to calling subscribers equipment to notify calling subscribers to operate their aforesaid devices and by such notification to indicate to calling subscribers that called subscribers have responded; and means governed by said switching mechanism for completing telephonic connection between called stations and the exchange prior to the complete es-- tablishmcnt of telephonic connection be tween calling and called stations whereby called stations maybe instructed to mention their numbers. A telephone exchange system including telephone lines extending from subscribers stations to an exchange at some of which stations are located devices requiring operation by calling subscribers after responses by called subscribers; link connectors at the exchange for uniting lines in conversation; switching mechanism; electro-magnetic mechanism within the control or" called subscribers and operated by called subscribers equipment when called sub-4 scribers respond to break telephonic connec-- tion between calling and called stations for telephonic current impressed upon calling lines at calling stations; electro-magnetic mechanism operated by the aforesaid devices at calling stations equipped therewith for operating said switching mechanism to complete connection betweenballingand called stations; means for completing telephonic connection between calling and called stations for telephonic current impressed upon called lines at called stations when telephonic connection is broken between calling and called stations for current impressed upon calling linesv at calling stations; means brought into association with calling lines by said switching mechanism when operated upon response of called subscribers for sending current to calling subscribers equipment to notify calling subscribers to operate their; aforesaid devices and by such notification to indicate to calling subscribers that called. subscribers have responded; and meansgoverned by said switching mechanism for com-. pleting telephonic connection between called aoeaees stations and the exchange prior to the complete establishment of telephonic connection between calling and called stations whereby called stations may be instructed. to mention their numbers,

16. A telephone exchange system including telephone lines extending from subscrlbcrs stations to an exchange at some of whichstations are. located devices requiring operation by calling subscribers aiter respouses by called Subscribers; link connectors at the exchange fornniting lines in conversation; switching mechanism included in the link connectors; electric-mag netic mechanism within the control or" called subscribers and operated by calledsubs scribers equipment when called subscribers respond to break telephonic connection between calling and called stations for telephonic current impressed upon callin lines at calling stations; electro-magnetic mecha- .nism operated by as aforesaid devices at calling stations equipped therewith tor operatlngsaid switching mechanism to com- ;plete connection between callingand called stations; means for completing telephonic connection between calling and called etations for telephonic current impressed upon called lines at called stations when telephonic connection is broken between calling and called stations for current impressed upon calling lines at calling stations; means brought into association with calling lines by said switching mechanism when operated upon response of called subscribers for send} ing' current to calling subscribers equipment to notify calling subscribers to operate their aforesaiddevices and by such DOtlfiCiltlOIliG indicate to calling subscribers that called subscribers have responded; and means governed by said switching mechanism for completing telephonic connection between called stations and the exchange prior to the complaete establishment of telephonic connection tween calling and called stations wherebycalled stations may be instructed to mention their numbers.

17. A telephone exchange system including telephone lines extending from subscrib ers stations to an exchange at some or which stations are located requiring opera tion by calling subscribers after responses by called subscribers; linkconnectors at the ibxchange for uniting lines in conversation;

switching mechanism; electro-magnetic mechanism within the control of called subscribers'aud operated by called subscribers equipment when called subscribers respond to break telephonic connection between calling and called'stations for telephonic current impressed upon calling lines at calling stations; electro magnetic mechanism operated by the aforesaid devices at calling sta-' tions equipped thereq iith for. operating said switching mechanism; to. complete connection between calling and called stations; and

means governed by said switching mechanism for completing telephonic connection between called stations and the exchange prior to the complete establishment of telephonic connection between calling and nism within the control of called subscribers and operated by called subscribers" equipment when called subscribers respond to break telephonic connection between calling and called stat-ions for telephonic current impressed upon calling lines at calling stations -electro-magnetic mechanism operated by the aforesaid devices at calling stations equipped therewith for operating said switching mechanism to'complete connection between calling and called stations: and means governed by said switchmg mechanism for completing telephonic connectionbetween called-stations and tl1e"exchange prior vto the complete establishment of telephonic connection between calling and called stations whereby called stations may be instructed to mention their numbers.

19. A telephone exchange system includingtelephone lines extending from subscribers stations to an exchange at some of. which stations are located devices requiring operation by calling subscribers after responses by called subscribers, there being means at the subscribers stations codperating with these devices and operable by responding called subscribers; link connectorsat the ex change for uniting. lines in .-..conversation; switching mechanism; elect-r0 -magnetic mechanism within the control of called subscribers and operated by called subscribers equipment when called subscribers respond to break telephonic connection between callmg tions; electromagnetic mechanism operated by the aforesaid devices at callingstations equipped therewith for operating said switching mechanism to complete connection between calling and called stations; means for completing telephonic connection between calling and called stations fortelephonic currentimpressed upon called lines at called stations when telephonic conuecand called stations for telephonic currentimpressed upon calling lines at calling sta-' tion is broken between calling and called stations for current impressed upon calling lines at calling stations; and'means governcd by sa1d;sw1tchmg mechanism for com pleting telephonic connection between called. stations and the exchange prior to the complete establishment of telephonic connection between calling and called stations whereby called stations may be instructed by the aforesaid devices at calling stations equipped therewith for operating said switching mechanism to complete connection between calling and called tat-ions; means for completing telephonic connection between calling and called stations for telephonic current impressed upon called lines at called stations when telephonic connect tion is broken between calling and called stations for current impressed upon calling lines at calling stations; and means governed by said switching mechanism for completing telephonic connection between called stations and the exchange prior to the" com plete establishment oi telephonic connection between calling and called stations whereby called stations may be instructed to mention their numbers.

QL'A telephone exchange system includ ing telephone lines extending from subscribers stations to an exchange at some of which stations are located devices requiring operation by calling subscribers after responses by called subscribers in order to complete connection between calling and called subscribers, there being means at the subscribers stations cooperating with these devices and operable by responding called subscribers; link connectors at the exchange for uniting lines in conversation; switching mechanism included in the link connectors for. breaking telephonic connection between calling and called stations for telephonic current impressed upon calling lines at calling stations; electromagnetic mechanism governed by the aforesaid devices at calling stations equipped therewith in cotiperation with the aforesaid means at stations of responding called subscribers for operating said switching mechanism to complete connection between calling and called stations; and means for completing telephonic connection between calling and called stations .coaaoes for telephonic current impressed upon called lines at called stations when teletion between calling and called stations for telephonic. current impressed upon calling lines at calling stations; electromagnetic mechanism governed by the aforesaid de vices at calling stations equipped therewith in cooperation with the aforesaid means at stations of respondingcalled subscribers for operating said switching mechanism to complete connection between calling and called stations; and means for complct' g telephonic connection between. callin and called stations for telephonic current impressed upon called lines at called stations when telephonic connection is broken bctwcen calling and called stations for current impressed upon calling lines at calli tions, there being means at responding called stations for operating this means.

23. A telephone exchange system includ ing telephone lines extending from subscribers stations to an exchange at some of which stations are located devices requiring operation. by calling subscribers alter responses by called subscribers in .order to complete connection between calling and called si'ibscribers, there being means at. the subscribers stations cooperating with these devices and operable by responding called subscribers; link connectors at the exchange for uniting lines in conversation; switching mechanism included in the link connectors for breakingtelephonic connection between calling and called stations for telephonic current impressed upon calling; lines at calling stations; electro-magno. mechanisn'i governed by the aforesaid devices at calling stations equipped thereivith in cooperation Wit-lithe. aforesaid means at stations of re spending called subscribers ole/rating said switching mechanism to complete connectibn between calling and. called stations; and means for completing telephonic connection. between calling and called stations for telephonic current impressed upon called lines at called stations When telephonic connection is broken between calling and called stations for current impressed upon calling Ill lines at calling stations, there being means at responding called stations for operating this means.

Q-l. A telephone exchange system including telephone lines extending from sub scribers stations to an exchange at some of which stations are located devices requiring operation by calling subscribers after responses by called subscribers in order to complete connection between calling and called subscribers, there being means at the subscribers stations cooperating with these devices and operable by responding called subscribers; link connectors at the exchange for uniting lines in conversation; switching mechanism for breaking telephonic connection between calling and called stations for telephonic current impressed upon calling lines at calling stations; electromagnetic -mechanism governed by the aforesaid devices at calling stations equipped therewith in cooperation with the aforesaid means'at stations of responding called subscribers for operating said'switching lllefil'itlilll filll to complete connection between calling and called stations; and electro-magnetic means in the link connectors for completing telephonic connection between calling and c lled stations for telephonic current impressed upon called lines at called stations when telephonic connection is broken between callingand called stations for current in'ipressed upon calling lines atcalling stations.

:25. A telephoneexchange system includ ing telephone lines extending from subscrib ers stations to an exchange at some of which stations are located devices requiring operation by calling subscribers after responses by called subscribers in order to complete connection between calling and called subscribers, there being means at the subscribers stations cooperating witi these devices and operable by responding called subscrib-- crs; link connectors at the exchange for uniting lines in conversation; switching mechanism included in the link connectors for breaking telephonic connection between calling and called stations for telephonic current impressed upon calling lines at calling stations; electromagnetic mechanism governed by the aforesaid devices atcalling stations equipped therewith in cooperation which stations are located devices requiring.

operation by calling subscribers after responses by called subscribers in order to complete connection bet-ween calling and called subscribers there being means atthe subscribers stationscooperating with these devices and operable by responding called subscribers; link connectors at the exchange for uniting lines in conversation; switching mechanism for breaking telephonic connection between calling and called stations for telephonic current impressed upon calling lines at calling stations; electromagnetic mechanism governed'bythe aforesaid devices at calling stations equipped therewith in cooperation with the aforesai means at stations of responding called subscribers for operating said switching mechanism to complete connection between calling and called stations; and electromagnetic means in the .link connectors for completing telephonic connection between calling and called sta' tions for telephonic current impressed upon called lines atcalled stations when telephonic connection is broken between calling and called stations for current impressed upon calling lines at calling stations, there being means at responding called stations for operating this means.

In witness whereof, I hereunto subscribe my name this third day of August A. 1)., 1912.

noaron L. JoHNsoN.

Witnesses:

L. CRAGG, I E'rrA L. WHITE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

